Several conflicting objectives are present in the field of high performance data acquisition for electrical power measurement, metering, and management. The first objective is high data resolution. The availability of high resolution analog-to-digital conversion methods, such as with sigma-delta modulators, combined with the power of state-of-the-art digital signal processors provides the capability to achieve significant levels of accuracy. Thus, complex signal processing may be performed on precise data using a conventional architecture, such as an architecture comprising one analog-to-digital converter and one processor per channel. However, a second objective is increasing signal processing bandwidth. An inherent tension exists between these objectives in that increasing bandwidth typically occurs at the expense of data resolution. One way to overcome this problem is to modify the bandwidth to suit the particular application or use. Likewise, analog-to-digital conversion has technological limitations associated with the difficulty of producing cost-effective, low noise, precise analog circuitry. Yet, a third objective is smaller integrated or electronic circuitry that also requires less power to operate. Thus, while a converter and a processor per channel may achieve such resolution or bandwidth requirements, the size and power for such a system may render it impractical or infeasible for most applications, particularly power measurement, metering, and management. Time multiplexing a single converter offers one possible approach, however, this further reduces bandwidth and increases the complexity of the analog circuitry necessary for implementation.
For a digital signal processing system to be attractive for use in power measurement, metering and management, several other features are desirable. The system should have the capability to perform digital signal processing at or near the site of data acquisition in order to reduce the amount of data to be transmitted via communication channels or to be "off-loaded" to other processors. Furthermore, it should be capable of real time or adaptive feedback control in order to permit its use at remote locations for extended periods of time. It should also have the flexibility to execute different complex processor operations, including multiplication, addition, frequency spectrum analysis, counting, threshold detection, integration and differentiation. A need thus exists for a device for use in processing signals that provides electrical power measurements, termed electrical power signals, in which the device has the capability for high performance data acquisition while also having: the capability to perform digital signal processing, the capability to realize a variety of different bandwidths, the flexibility to be reconfigured, and the capability to perform real time or adaptive feedback control.